1. Field of the Invention
The present invention relates to a power module and a display device that can be applied to an LED TV, and the like.
2. Description of the Related Art
Recently, a Flat Panel Display (FPD) which is a new technology which is appropriate for a multi-media system having a high resolution and a large-sized screen has become prominent in the display industry, as a replacement for a Cathode Ray Tube (CRT).
In particular, in the case of a large-sized display, a Liquid Crystal Display (LCD) TV has become prominent and has been expected to grow in prominence henceforth in view of price and marketability.
A Cold Cathode Fluorescent Lamp (CCFL) has been used as a backlight light source in the LCD TV according to the prior art. However, recently, the use of a Light Emitting Diode (LED) has been gradually increased due to various advantages including power consumption, life span and environmentally friendly characteristics.
Therefore, as the backlight unit that uses the LED becomes lower in price and more compact, the thickness of the flat screen TV has been gradually reduced to be slimmer, along with the internal power module of the flat screen TV.
A display device according to the prior art is configured to include a panel, a backlight unit that supports the panel, a circuit board that supplies power to the light source of the backlight unit, a transformer that is mounted on the circuit board and supplies the power to the circuit board, and a back cover that is coupled to the backlight unit and covers the circuit board and the transformer.
As the thickness of the display device, as constituted above, has been gradually reduced, a back cover made of a conductive material that can be more thinly formed, such as an iron plate, has been adopted, instead of a back cover made of a thick plastic material.
Further, in order to reduce the thickness of the display device, the transformer and the back cover that are mounted on the circuit board have been gradually moved closer to each other.
Under the circumstances, as the transformer and the back cover have been moved closer to each other, the following problems may arise.
First, in the case that the transformer is a resonant type in which a zero voltage switching (ZVS) operation is performed, when the conductive back cover is closer to the transformer, capacitance is formed between the transformer and the back cover and thus, switching loss is generated and a resonant frequency is shifted due to such capacitance, thereby causing a fatal problem in that the transformer malfunctions.
Also, when the transformer is closer to the back cover, magnetic flux is formed from the transformer to the back cover, thereby causing a problem in which power consumption is generated through the conductive back cover. That is, when the back cover is a conductive back cover such as an iron plate, the magnetic flux generated by the transformer is leaked to the back cover due to magnetic interference between the transformer and the conductive back cover of the circuit board during the operation of thereof, thereby causing problems wherein the overall power consumption is increased and the temperature of the transformer is raised due to power consumption generated from the back cover.